If you can't find it... handlebar end plugs

[Clydesdale Scot]

In another of the ongoing stories
If you can't find it... Shockstop 'honking' rubbers
If you can't find it... cable bands
I was wanting some period handlebar end plugs. I had some Velox expander plugs, but they came later to the period I was after.
Danny found some used Shockstop bar end plugs
http://www.bicycles.net.au/forums/viewt ... 7#p1391179
and Quang rotated the profile and 3D printed one.

About the same time I purchased a NOS set. Not cheap, and nor was the postage from the UK.
Then I had to learn how to make the mould and cast them.
David's thread on Bike Forums has been an excellent guide
How to make reproduction Vittoria hoods and his photos on his Flickr album
https://www.flickr.com/photos/68123172@ ... 2070020831
For those on Classic Rendezvous, David has recently shown his latest project, reproduction Vittoria handlebar Plugs.

I had a vacuum pump that I use for casting leather saddles, so with a few extra bits I had a device to put the mixture under a vacuum to minimise any trapped air bubbles.
But I also wanted a pressure tank to place the cast item under pressure to squeeze down any remaining bubbles before the urethane solidified.
Recently I bought a pressure tank at a good price.
So no more excuses.
Time to play... with Duplo and a Lego board and clay.

[Clydesdale Scot]

mould casting by philip.knight, on Flickr

I created a bed in the special modelling clay to raise the bar end plug up. I then needed the fill in and around the original to exactly half way up the sides. I used the original parting line clearly evident. I added some depressions to help locate the two halves and added the silicone.
Then waited for that to set overnight.
Carefully removing the Duplo sides to the mould, then carefully removed the modelling clay.
Flipped the cast top and the original plug over, sealed up all the Duplo joins, applied a release agent so the silicon wouldn't stick to the previously cast piece and then cast the complementary half.
I had no idea if the first half had work, or was so full of bubbles to render it unusable.
Mould silicon is not cheap.

[Clydesdale Scot]

This morning, with some trepidation, I removed the Duplo sides and then gently prised the two mould sections apart.
The release agent worked.
Then I removed the original plug, and carefully inspected the result.
mould opened by philip.knight, on Flickr

You can see the original has the parting line flashing evident, and this is seen on the red halves to the mould.
Thye half on the left was the first half moulded and the half on the right is the second half and is an exact replica of the modelling clay shape I needed to make.
I need to clean up the remaining modelling clay, and cut through the injection hole and the vent sprue.
I was very pleased with the accuracy of the mould.
Just like the YouTube videos!
And now I need to wait for the casting urethane to arrive at the casting suppliers.
So there are more instalments to come.

Looks like I can play with my kid's Duplo and Lego base until they produce some grandchildren.
Then I can show the grandchildren how you really play with Duplo and modelling clay.

[flying dragon]

Awesome!
I made very similar moulds when I studied sculpture at art school. We were pouring wax into the moulds to then cast bronze.
Fun project!

[Clydesdale Scot]

freshly made by philip.knight, on Flickr

It has finally happened.
After procrastinating on this for a while (but what happens if it doesn't work out!) I made a second mould so I could cast two at a time.
But before I did that I was concerned at the finish of the product. I didn't want the bubbling that is on the Honking rubbers which I have made, but are rejected for use.
So I invested in a vacuum tank to remove trapped air bubbles from the mixture prior to casting.
Then I was still concerned, so I researched further and found if you pressurised the mould during the curing process, any residual air bubbles are squeezed town to micro bubbles which are not visible.
Then it is all of the fittings to connect the equipment.
Then I needed to do a few other non-bike things.

But I got back to this last weekend and made the matching mould, and yesterday cast the first plugs. No bubbles. So all that research and equipment gave the result I was after.
The casting webbing is identical to the NOS ones I purchased, so it is authentic.
Now to cut the sprues and put them in the parts bin.
And get some blue pigment to make some for Dad's Spearman. Then I can take out the wrong date Velox plugs and put in my minty-fresh Shockstop handlebar plugs. A lot of effort to get things as I want them.

Background book is a Brown Bros 1952 catalogue.

Robert, the image has two focus points and is a stacked 5 exposure image.

[Gordon1]

A very impressive performance, again.

If available to the public I would like to purchase 2 sets . While I’m mostly happy using a cork there are two bikes I would like to upgrade.

Your ability to produce a small item that can be hard or impossible to get or when you do it is deteriorated beyond use is to be commended.

[redsonic]

For people keen to try something like this, I have had some success reducing air bubbles using one of those vacuum bags that you store clothes in. The whole cast needs to be in a wire or mesh box/container to stop the bag collapsing onto it. You then just connect a vacuum to the bag valve.